Camera module and method of manufacturing the same

ABSTRACT

Camera module embodiments and methods of manufacturing camera modules are provided. A camera module can include a housing and a printed circuit board having an image sensor. The housing can be mounted to the printed circuit board using a surface mount technology. In a method of manufacturing the camera module, the image sensor and the housing can be mounted to the printed circuit board, and a lens and a filter can be coupled to an upper portion of the housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application No. 11/684,927,filed Mar. 12, 2007 now U.S. Pat. No. 7,780,365, which claims thebenefit under 35 U.S.C. §119 of Korean Patent Application No.10-2006-022840 filed on Mar. 10, 2006, which are hereby incorporated byreference in their entirety.

BACKGROUND

As mobile devices are miniaturized and become multi-functioned,components for communication functions, camera functions, and audioreproduction functions are being modularized and remarkablyminiaturized. Markedly, mobile devices such as mobile phones and PDAsinclude a camera function using a compact camera module (CCM).

A CCM includes an image sensor such as a charge coupled device (CCD) ora complementary metal oxide semiconductor (CMOS). The CCM converts lightenergy into an electric signal using the image sensor to obtain imagedata. In addition, the image data can be transmitted to and stored in acorresponding device.

FIG. 1 is a cross-sectional view illustrating a conventional cameramodule 10.

Referring to FIG. 1, the camera module 10 includes a printed circuitboard 20, an image sensor 30, a housing 40, and a lens barrel 50.

Passive elements and the like are mounted on the upper surface of theprinted circuit board 20 using a surface mount technology (SMT).

The image sensor 30 is disposed on the upper surface of the printedcircuit board 20. An epoxy (not shown) is spread to the upper surface ofthe printed circuit board 20, and then the image sensor 30 is attachedon the epoxy. In addition, a plurality of electrode pads 34 of the imagesensor 30 are connected to an electrode terminal 22 of the printedcircuit board 20 using a wire 36.

In addition, the housing 40 is bonded to the edge of the upper surfaceof the printed circuit board 20. An epoxy 24 is spread to the edge ofthe upper surface of the printed circuit board 20, and then the housing40 is attached on the epoxy 24. The epoxy 24 spread to the edge of theupper surface of the printed circuit board 20 is cured at apredetermined temperature to fix the housing 40.

Meanwhile, the lens barrel 50 including a glass filter 52 and a lens 54is coupled to an upper portion of the housing 40. For example, a lensbarrel thread 56 is formed in the outer surface of the lens barrel 50and a housing thread 44 is formed in the inner surface 42 of the housing40. The lens barrel 50 is coupled to the housing 40 using the threads 56and 44.

In the camera module, a coupling defectiveness between the housing 40and the printed circuit board 20 may occur according to the amount ofthe spread epoxy 24 for fixing the printed circuit board 20 to housing40. For example, when the epoxy 24, which is a spot type epoxy, isspread on the upper surface of the printed circuit board 20, a portionof the housing 40 to which the epoxy 24 is not spread may have a gap. Aslight enters through the gap between the housing 40 and the printedcircuit board 20, the picture quality obtained from the image sensor 30may deteriorate.

When the epoxy 24 is excessively spread to the edge of the upper surfaceof the printed circuit board 20, a fixing defectiveness of the housing40 occurs according to a curing temperature of the epoxy 24 havingelasticity and viscosity.

In addition, when the epoxy 24 is excessively spread, the epoxy 24 mayget out of the interface between the housing 40 and the printed circuitboard 20 and invade the image sensor 30 to contaminate the photodetecting area 32.

In addition, the housing 40 fixed on the printed circuit board 20 may betilted by viscosity variations of the epoxy 24, and thus the center ofthe lens 54 placed on the upper portion of the housing 40 is not alignedwith the center of a pixel region of the image sensor 30. This resultsin a defective assembly of the camera module. The housing 40 is tiltedto cause a shift in focus. The shift in focus is detected after thecamera module is assembled. Therefore, the camera module should bedisassembled and the assembly yield is decreased.

BRIEF SUMMARY

An embodiment of the present invention provides a camera module fixing ahousing on a printed circuit board using a surface mount technology anda method of manufacturing the same.

An embodiment of the present invention provides a camera moduleimproving assembleability and productivity thereof and inhibiting ahousing from being tilted to align the optical axis of an image sensorby fixing the image sensor and the housing to a printed circuit boardusing the surface mount technology and a method of manufacturing thesame.

An embodiment of the present invention provides a camera modulecomprising an image sensor, a printed circuit board including the imagesensor, a housing fixed to the printed circuit board by a surface mounttechnology (SMT), and a lens part provided with the housing.

An embodiment of the present invention provides a method ofmanufacturing a camera module, the method comprising attaching an imagesensor to a printed circuit board, fixing a housing to the printedcircuit board using a surface mount technology (SMT), and coupling alens part including a lens and a filter to an upper portion of thehousing.

According to embodiments of the present invention, the housing can bebonded to the printed circuit board including the image sensor using ametal bonding method. Therefore, light may be inhibited from enteringbetween the housing and the printed circuit board, and the tilt of theoptical axis may be inhibited.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating a conventional cameramodule;

FIG. 2 is a cross-sectional view illustrating a camera module accordingto an embodiment of the present invention;

FIG. 3 is an exploded perspective view illustrating a camera moduleaccording to an embodiment of the present invention;

FIG. 4 is a cross-sectional view illustrating one example of a housingaccording to an embodiment of the present invention;

FIGS. 5 and 6 are cross-sectional views illustrating other examples of ahousing according to an embodiment of the present invention;

FIG. 7 is a cross-sectional view illustrating another example of acamera module according to an embodiment of the present invention; and

FIG. 8 is a flow chart illustrating a method of manufacturing a cameramodule according to an embodiment of the present invention.

DETAILED DESCRIPTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

FIG. 2 is a cross-sectional view illustrating a camera module 100according to an embodiment of the present invention.

Referring to FIG. 2, the camera module 100 includes a printed circuitboard 110, an image sensor 120, a housing 130, and a lens barrel 150.

The printed circuit board 110 including a predetermined circuit patternmay be a hard printed circuit board or a flexible printed circuit board.The circuit pattern includes electrode terminals 112 and a firstmounting portion 114.

The first mounting portion 114 can be a gold (Au) and/or nickel (Ni)plated copper foil pad corresponding to the shape of housing 130 and canbe formed along a periphery of the housing 130.

The image sensor 120 includes a photo detecting area 122. Many sensordevices responding to light can be integrated on the image sensor 120.

The image sensor 120 may be a charge coupled device (CCD) or acomplementary metal oxide semiconductor (CMOS). The image sensor 120includes a semiconductor chip packaged using, for example, a ball gridarray (BGA), a chip scale (size) package (CSP), or a chip on board (COB)technology. The embodiments will be described with reference to a CSPtype image sensor.

The image sensor 120 can convert images captured from the photodetecting area 122 through the lens barrel 150 to electric signals,where the image sensor 120 is attached on an upper surface or a backsurface of the printed circuit board 110, thus securing an optical path.

A passive element(s) and the image sensor 120 can be disposed on theupper surface of the printed circuit board 110, where the image sensor120 can be disposed on the electrode terminal 112 of the printed circuitboard 110. In addition, the housing 130 around the image sensor 120 canbe disposed on the first mounting portion 114 of the printed circuitboard 110.

The housing 130 supplies an optical path to the image sensor 120disposed on the upper surface of the printed circuit board 110.

A light guide portion 131 is formed on an upper portion of the housing130, and a support portion 135 is formed on a lower portion of thehousing 130.

A second mounting portion 140 is formed at the lower end 133 of thesupport portion for the support portion 135 to be mounted on the edge ofthe upper surface of the printed circuit board 110. The second mountingportion 140 may be a metal plate inserted into the support portion 135when the housing 130 is formed. The gold (Au) and/or nickel (Ni) platedmetal plate can have, for example, a circular or a polygonal shapeaccording to the shape of the support portion 135 of the housing 130.

The second mounting portion 140 can be bonded to the first mountingportion 114 formed on the printed circuit board 110 by a surfacemounting technology. At this time, solder (not shown) can be interposedbetween the first mounting portion 114 formed on the printed circuitboard 110 and the second mounting portion 140 of the housing 130. Thesolder is melted at a lower melting temperature than those of the firstand second mounting portions 114 and 140 to bond the first mountingportion 114 to the second mounting portion 140.

The solder may be a metal having a lower melting temperature than themetal layers of the first and second mounting portions 114 and 140. Forexample, the solder may be a soft lead having a lower meltingtemperature than that of, for example, Pb (e.g., 327° C.) or a hard leadhaving a melting temperature of 450° C. or more. The solder may bespread on the first mounting portion 114 as a solder paste.

For example, solder powder and a flux can be mixed to obtain the solderpaste having an appropriate viscosity for printing. In a specificembodiment, after placing a metal mask on the printed circuit board 110,the solder paste can be squeezed by a squeeze to be spread on the firstmounting portion 114 of the printed circuit board 110.

In the camera module, the passive element(s), the image sensor 120, andthe housing 130 can be mounted on the printed circuit board 110 using asurface mount technology (SMT).

The lens barrel 150 can be coupled to the inner surface 132 of the lightguide portion 131 of the housing 130. For example, a lens barrel thread156 can be formed in the outer surface of the lens barrel 150 and ahousing thread 134 can be formed in the inner surface 132 of the housing130 such that the lens barrel 150 is coupled in the housing 130 usingthe threads 156 and 134.

The lens barrel 150 may have a barrel shaped frame and can include afilter 152 and a lens 154. The filter 152 may be located between theimage sensor 120 and the lens 154 and can include, for example, a glassfilter or an IR (infrared ray) cut filter. The lens 154 can incorporateone or more lenses, and condenses the inputted light on to the photodetecting area 122.

FIG. 3 is an exploded perspective view illustrating a camera moduleaccording to an embodiment of the present invention.

Referring to FIG. 3, a copper foil can be formed on one side or bothsides of an insulation layer to form the printed circuit board 110. Thecopper foil forms a circuit pattern including the plurality of electrodeterminals (not shown) and the first mounting portion 114 using aphotolithography process. The region except for the electrode terminals(not shown) and the first mounting portion 114 can be protected by asolder resist.

A plating layer may be formed on the surfaces of the electrode terminal(not shown) of the printed circuit board 110 and the first mountingportion 114. The plating layer of the first mounting portion 114 may beformed when the plating layer of the electrode terminal (not shown) isformed. The reference number 115 indicates a line supplying power forplating.

The image sensor 120 is disposed on a region of the printed circuitboard 110, and an image sensor is mounted thereupon. The second mountingportion 140 formed on the bottom surface of the housing 130 can bedisposed on the first mounting portion 114 of the printed circuit board110. In addition, the second bonding portion 140 provided at the lowerend of the housing 130 can incorporate an area parallel with a side ofthe housing 130 and/or a non-parallel area extended from the parallelarea. In a further embodiment, the non-parallel area can be furthermodified by at least one vertical bend.

The passive element(s), the image sensor 120, and the housing 130 can bemounted to the upper surface of the printed circuit board 110 using asurface mount technology (SMT).

As an example of an SMT for the housing 130, solder can be spread afterthe second mounting portion 140 formed on the bottom surface of thehousing 130 is aligned with the first mounting portion 114 of theprinted circuit board 110. After that, a heater REFLOW supplies heat andthe solder spread on the printed circuit board 110 is melted to bond thefirst mounting portion 114 to the second mounting portion 140.

The solder is a means for a metal bonding between the first mountingportion 114 and the second mounting portion 140. The solder may beselected considering its attachability, melting point, mechanicalproperties, and cost. Since a solder bonding type includes Pb, which maycause a nerve disorder in the human body, a lead free solder bondingtype is preferrably used.

Sn—Cu based, Sn—Ag—Cu based, Sn—Bi based, and Sn—Zn based lead freesolders are widely used. For example, the Sn—Cu based lead free solderhas a melting point of 227° C., the Sn—Ag—Cu based lead free solder hasa process temperature of 218° C.

When the first mounting portion 114 of the printed circuit board 110 isa Cu pad, the attachment defectiveness of the solder to the firstmounting portion 114 can be reduced or inhibited by selecting anappropriate solder. In addition, the exact amount of the solder can beprinted on the surface of the printed circuit board 110 on which thehousing 130 is placed.

As illustrated in FIGS. 2 and 3, the housing 130 can be fixed to theedge of the upper surface of the printed circuit board 110 using a metalbonding method and is capable of sealing the outside of the image sensor120. Therefore, the light except for the light induced through the lenspart 154 can be reduced or inhibited from being inputted to the photodetecting area 122 of the image sensor 120.

In addition, the housing 130 to which the lens barrel 150 is coupled,can be fixed to the correct position of the printed circuit board 110.Therefore, the optical axis of the lens part 154 over the image sensor120 can be properly aligned with that of the photo detecting area 122.

One example of a housing 130 is illustrated in FIG. 4.

As illustrated in FIG. 4, the second mounting portion 140 protrudesalong the lower end of the support portion 135 of the housing 130. Inone embodiment, the second mounting portion 140 can be provided andengaged as a single unit with the support portion 135 when the housing130 is injection molded.

The second mounting portion 140 may be a metal plate or a gold (Au)and/or nickel (Ni) plated metal plate. The shape of the second mountingportion 140 can be a vertical bar type.

Another example of a housing 130 is illustrated in FIG. 5.

As illustrated in FIG. 5, a second mounting portion 145 formed at thesupport portion 135 of the housing 130 can include a lower portion ofits vertical plate that bends horizontally outward or inward. The secondmounting portion 145 has an area to which the first mounting portion canbe bonded. The area of the second mounting portion 145 is larger thanthat of a simple vertical plate because of the horizontally bendingportion.

Another example of a housing 130 is illustrated in FIG. 6.

As illustrated in FIG. 6, a second mounting portion 146 formed at thesupport portion 135 of the housing 130 can include a lower portion ofits vertical plate that bends horizontally outward or inward and an endportion of the bent portion vertically bent downward. That is, thesecond mounting portion 146 can have a stairway shape having one or morebent portions. A horizontal portion 147 bent from the vertical plate cancontact an upper surface of the first mounting portion 114 illustratedin FIG. 3. A vertical portion 148 bent from an end portion of thehorizontal portion 147 can contact an outer surface of the firstmounting portion 114 illustrated in FIG. 3. Therefore, the light fromthe outside of the housing can be effectively blocked. The verticalportion 148 may have the same or smaller height than the thickness ofthe first mounting portion 114 illustrated in FIG. 3.

FIG. 7 is a cross-sectional view illustrating another example of acamera module 200 according to an embodiment of the present invention.Here, the camera module 200 can be coupled to a substrate using a flipchip bonding method, rather than a wire bonding method.

Referring to FIG. 7, the camera module 200 includes a printed circuitboard 210, an image sensor 220, a housing 230, and a lens barrel 250.

A light guide hole 215 can be formed in the printed circuit board 210 inorder to secure the optical path of the image sensor 220. A firstmounting portion 214 can be formed on the edge of the upper surface ofthe printed circuit board 210.

The image sensor 220 can be coupled to the printed circuit board 210,with a photo detecting area 222 being at the center of the light guidehole 215 of the printed circuit board 210.

The image sensor 220 can be electrically connected to the printedcircuit board 210 through an electrode terminal 212 formed on the backsurface of the printed circuit board 210. The gap between the imagesensor 220 and the printed circuit board 210 can be filled with asealant (not shown) to reduce or inhibit needless light from beinginputted or leaked. The sealant may be, for example, an epoxy orsilicon.

The image sensor 220 can be mounted on the back surface of the printedcircuit board 210 by a flip chip method (e.g., a chip on film (COF)method). The COF method is a method of attaching various chips to aflexible printed circuit board (FPCB). That is, the gold in an imagesensor can be directly bonded to the stannum (Sn) in the FPCB by the COFmethod by supplying a predetermined heat and pressure. An image sensoris directly bonded to the back surface of an FPCB without an additionalmeans by the COF method. Therefore, compared to a ball grid array (BGA)method, the COF method reduces package costs.

In addition, the size of an FPCB can be reduced to one fourth of aconventional size by the COF method. An FPCB of the COF method can havean area which is just large enough for various parts or chips to beplaced on the FPCB. In addition, compared to an anisotropic conductivefilm (ACF) method the COF method is excellent in product safety andspace utilization.

Referring again to FIG. 7, the first mounting portion 214 can be formedon the edge of the upper surface of the printed circuit board 210. Thefirst mounting portion 214 can be bonded to a second mounting portion240 formed on the lower end of a support portion 235 of the housing 230by a surface mounting technology using a metal bonding method. Thehousing may have a size which is larger than that of the sensor guidehole 215 or does not affect the optical path.

In addition, the lens barrel 250 can be coupled to an upper portion ofthe housing 230. That is, the lens barrel 250 including a filter 252 anda lens 254 can be attached to a light guide portion 231 of the housing230 using threads 234 and 256. The filter 252 can include, for example,a glass filter or an IR cut filter.

In another embodiment example, the first mounting portion 214 of theprinted circuit board 210 can be bonded to the second mounting portion240 of the housing 230 using an ultrasonic bonding method. Theultrasonic bonding method is a method of bonding the first mountingportion 214 to the second mounting portion 240 by rubbing the firstmounting portion 214 of the printed circuit board 210 with the secondmounting portion 240 of the housing 230 using a low pressure and astrong ultrasonic vibration. The ultrasonic bonding method can reduce orinhibit breakages of the housing 230 and the printed circuit board 210by the REFLOW process.

In yet another embodiment example, the first mounting portion 214 of theprinted circuit board 210 can be bonded to the second mounting portion240 of the housing 230 by projecting laser beam at contact surfaces ofthe first and second mounting portions 214 and 240. The method using alaser beam can reduce or inhibit breakages of the housing 240.

FIG. 8 is a flow chart illustrating a method of manufacturing a cameramodule according to an embodiment of the present invention.

Referring to FIG. 8, an image sensor can be attached to a printedcircuit board (S101).

The housing can be disposed on an upper surface of a printed circuitboard. In operation, light is inputted to the image sensor through thehousing of the printed circuit board.

The image sensor and the housing can be fixed to the printed circuitboard using a surface mount technology (SMT) (S103). The SMT used to fixthe housing to the printed circuit board can involve a method ofmounting a metal plate formed at the lower end of the housing to aplated pad formed on the edge of the upper surface of the printedcircuit board, such as, for example, a surface mounting technology for asolder bonding. When the image sensor and the housing are mounted to theprinted circuit board using the SMT, the image sensor is located in thehousing, and an optical path arrives at the image sensor through anupper portion of the housing.

A lens barrel can be coupled to the housing (S105). The lens barrel canbe coupled to the upper portion of the housing without invading theoptical path. Here, the lens barrel can be coupled to the upper portionof the housing before or after the metal bonding of the SMT.

The camera module according to an embodiment of the present inventionreduces the number of a camera module manufacturing processes bymounting various elements, the image sensor, and the housing to theprinted circuit board using SMT. In addition, the camera moduleaccording to an embodiment of the present invention is capable ofsecuring the reliability of the image quality of the camera module byreducing or inhibiting stray light from being introduced to the imagesensor because of the mounted housing.

In addition, the center of the lens can be exactly aligned with thecenter of the image sensor because the housing can be coupled to theprinted circuit board without tilting. Therefore, the assembly accuracyof the camera module can be improved to inhibit the inferiority of thepicture quality caused by missing the focus and the contamination of theimage sensor caused by an epoxy adhesive.

In addition, compared to an epoxy bonding of the housing to the printedcircuit board, the camera module according to an embodiment of thepresent invention reduces or inhibits the contamination of an imagesensing portion typically caused by an epoxy, and greatly reduces anepoxy curing time to improve the yield of the camera module process.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A camera module comprising: a printed circuitboard including a circuit pattern; an image sensor electrically coupledto the printed circuit board; a housing fixed to the printed circuitboard, wherein the housing includes a light guide portion and a supportportion disposed at a lower portion of the light guide portion; and alens part coupled to the housing, wherein the circuit pattern includesan electrode terminal, wherein the image sensor is electricallyconnected to the electrode terminal, wherein a lower surface of thesupport portion includes a metal, wherein a portion of the printedcircuit board faced with the support portion includes a metal, andwherein the support portion is electrically connected to the portion ofthe printed circuit board.
 2. A camera module comprising: a printedcircuit board including a light guide hole and a first mounting portion;an image sensor including a photo detecting area and disposed on a backsurface of the printed circuit board, wherein the image sensor isconnected to an electrode terminal on the back surface of the printedcircuit board; a housing disposed on a front surface of the printedcircuit board, wherein the housing includes a second mounting portion;and a lens part coupled to the housing, wherein the lens part, the lightguide hole, and the photo detecting area are aligned, and wherein thefirst mounting portion and the second mounting portion are formed of ametal and bonded to each other.
 3. The camera module according to claim2, wherein the lens part includes a lens and a filter.
 4. The cameramodule according to claim 3, wherein the filter is disposed between thelens and the light guide hole.
 5. The camera module according to claim3, wherein the filter includes a glass filter or an IR cut filter. 6.The camera module according to claim 3, wherein a dimension of the lightguide hole is greater than a dimension of the filter.
 7. The cameramodule according to claim 2, wherein the photo detecting area isdisposed in the light guide hole.
 8. A camera module comprising: aprinted circuit board including a first mounting portion; an imagesensor electrically coupled to the printed circuit board, wherein theimage sensor includes a photo detecting area; a housing including asecond mounting portion; and a lens part coupled to the housing, whereinthe first mounting portion and the second mounting portion are formed ofa metal, and wherein the first mounting portion and the second mountingportion are bonded to each other.
 9. The camera module according toclaim 8, further comprising a solder disposed between the first mountingportion and the second mounting portion.
 10. The camera module accordingto claim 9, wherein the solder includes at least one of Sn—Cu basedsolder, Sn—Ag—Cu based solder, Sn—Bi based solder, and Sn—Zn basedsolder.
 11. The camera module according to claim 8, wherein the secondmounting portion is protruded from a lower end of the housing.
 12. Thecamera module according to claim 8, wherein the second mounting portionis injection molded with the housing.
 13. The camera module according toclaim 8, wherein the second mounting portion includes a vertical plateand a bending portion connected to the vertical plate.
 14. The cameramodule according to claim 13, wherein the bending portion is benthorizontally outward or inward.